1. Field of the Invention
The present invention relates to a hydraulically operated rotary drive including a housing which can be connected to a source of pressure fluid, a rotatable shaft, and a belt which is arranged at least partially within the housing with the formation of movable pressure chambers and is functionally connected to the shaft.
2. Description of the Related Art
A hydraulically operated rotary drive of this type is known from U.S. Pat. No. 4,838,148. In that known rotary drive, a flexible belt is arranged within a housing having a hollow space and forms movable pressure chambers within the housing. These movable pressure chambers are formed by the provision of rollers or roller-shaped bodies within the housing, over which the belt is passed, forming at least one open loop. The movable pressure chambers 14 are constructed and operate in the manner disclosed, for example, in above-mentioned U.S. Pat. No. 4,838,148. Thus, the shaft 3 is rotated by the belt 15 when pressure fluid is admitted to one of the chambers 14.
The belt is movable within the hollow space in such a manner that by its revolving it changes the open region of the loop which forms the pressure chambers. This change is effected in the final analysis by the pressure fluid introduced into the movable pressure chambers. The two outer edges of the belt rest in the housing or in the hollow space in such a manner that, on the one hand, it is still readily movable while, on the other hand, it seals in hydraulically tight manner. The change or movement of the belt effected by the impact of pressure with the formation of the aforementioned open loop results, upon travel over the rotatable roller arranged within the housing, in a rotary movement which can be tapped off. This rotary movement is conducted outward via a shaft. This known development has the disadvantage that it cannot readily be extended to mechanical or mechanico-electrical structural groups. The difficulty in such external extension is not solely the mechanical coupling but also the effecting of electrical connections and connections of pressure fluid from one structural part or module to the other.